Corrugating die



April 2,1946. J, A. WATT ET AL 2,397,532

CORRUGATING DIE x Filed March 9, 1944 2 Sheets-Sheet 1 JAMES A. WATT BYALFRED J. PERKINS ATTORNEY pr 2, 1946- J. A. WATT ETAL 2,397,582

CORRUGATING DIE Filed March 9, 1944 2 Sheets-Sheet 2 INVENTO'R JAMES A.WATT BY L RED J. PERKINS ATToRNEY Patented Apr. 2, 1946 CORRUGATING DIEJames A. Watt and Alfred J. Perkins, Buffalo,

N. Y., assignors to Curtiss-Wright Corporation, a corporationof DelawareApplication March-9, 1944, Serial'No. 525,788

4 Claims.

This invention relates to improvements in corrugating dies and, althoughnot necessarily limited to such use, is characterized by features whichrender it of. particular utility in connection with the formation ofstraight-sided corrugations.

Corrugating dies, as heretofore proposed, have the objection that whenutilized in connection with the annealed sheets, the subsequent heattreatments to which the latter are subjected for hardening purposescause warping f the sheets and thereby render it difiicult, and in manyinstances impossible, to maintain the required tol erances. On the otherhand, when the sheets are re-hardened and a brake employed to form thecorrugations it is even more difficult to maintain the requiredtolerances. Regardless of the method employed, therefore, the finishedcorrugated sheet may be warped or the corrugations thereof may beinaccurately formed.

The principal object of the present invention is to overcome the aboveobjections, this object contemplating dies which are available for usein connection with the corrugating of hardened sheets and which when soemployed are adapted to form corrugations which are uniform and highlyaccurate as to dimensions and to the locations between the centers ofthe crest portions.

A further object is a novel design and arrangement of the dies, wherebyto enable the corrugations to be formed rapidly and without stretching,thinning, stressing or marring of the walls thereof. I

The invention is illustrated in the accompanying drawings, in which:

Figure 1 is an end elevational view of dies embodying the features ofthe invention, the dies being shown at the completion of a stroke inwhich a pilot corrugation is formed.

Figure 2 is a similar view showing the relation of the dies when a sideand the bottom of a second corrugation are formed.

Figure 3 is a similar view showing in full lines the relation of thedies just prior to the operation of the latter to form the thirdcorrugation and in dotted lines the open position of the dies.

Figure 4 is a similar view showing the relation of the dies aftercompletion of the stroke in'which the third corrugation is formed.

Figure 5 is a fragmentary elevational view, partially in section, of theentrance side of the die set.

Figure 6 is a similar view also partially in section, of the oppositeside of the die set.

Figure 7 is a detail sectional view.

The dies are'illustrated in connection with a powerpress which issufiiciently indicated for the purpose in view byashowing of the bed I0and ram I I thereof. A punch assembly I2 is carried by the latter. Thesaid assembly, which includes elongated, parallel punch elements I3, I4and I5, also includes a holder IS, the latter being carried by parallelbars "which are secured to the ram II- by clamps I B. The punchelementI4 and an angle member I9 which are suitably secured together as a unitare connected to the holder I6 by bolts Ml (Figure 1), the said unitbeing normally held in the extended position shown in Figure 3 bysprings 21, The punch element I4 and angle member I9 carry the-punchelement I5 either in an operative, or extended, position or in aninoperative, or retracted, position. To this end a bar 22 which issuitably secured to the overhanging flange on the punch element It isformed with a series of spaced lugs 23. The latter cooperate with asimilar series of lugs H formed on the top of the punch element I5, theJugs iii-being adapted either angle member I9 and in the punch elementsI4 and I5. By removing the pins 25, shifting the punch element I5lengthwise and then elevating it, the lugs on the punch element may becaused to register with and 'enter the spaces between the lugs on thebar 22. The punch element I5 is thereby withdrawn to an inoperativeposition in which it may be locked by the pins 25.

' The punch element I3 is suspended from the holder IS in a positionalongside the punch elerhent I4 by a bar 26. The latter may be securedto the holder by a key 21 and bolts 28 either in a position' to hold thepunch element I3 in an extended, or operative, position or in aretracted, or inoperative position, the bar 26 being formed with slots29 (Figure 5)' for accommodating the bolts 28 in either position of saidbar. Backing blocks 38*are' preferably employed in connection with thebar 26, being'arranged between the latter and the bars l1 when thepunch-element I3 occupies its extended position. When the said elementis to be withdrawn to its retracted position, the blocks are movedto oneside, as indicated in dotted lines in Figure 5, so that they may enterthe spaces between the bars H.

The punch element I 3 is pivotally connected to the bar 26 by a shaft3|. The'latter is journaled in a bearing 32 which is'i'ormed in theunderside of the bar 26, being secured therein by caps 33 and beingformed with half-round sections 34 to which the punch element is securedby bolts 35.

'The shaft 3| supports the punch element l3 so that it may swingeitherto a'position in which it contacts the side of the punch element M or tothe angular position shown in Figure 3. The punch elementf I3 is biased.to the latter position by spring-loaded pins 31 which are carried bythe former and which act against the adjacent side wall of the punchelement .|4.- Outward movement of the punch element |3 in response tothe spring-loaded pins 31 is limited by enga ement of an angularlyinclinedshoulder 39 on the said element with the underside of the bar 26have been moved downwardly a predetermined A die member 4|] cooperateswith the punch assembly described. The said member (Figure 3) isnormally supported above a bed plate 4| by air-actuated plungers 42, thesaid bed plate rest-. ing on the bed ID of the press and carrying guides43 which are accommodated in bores 44 formed in. the holder Hi. The diemember 40 may alsooccupy a position as shown in Figure 1, in which it isseated on thebedplate 4|, suitable means being provided forjguiding thedie member bedistance by the ram, an angularly inclined wall 50 on theunder side of the die member 40 engages'an underlying wall 5 l of anelongated rotatable member 52. The latter is journaled in spaced bearingblocks 53 (Figure 5) and is normally held in the angular position shownin Figure 3 ,by springs 54 which at one end are connected to arms55carried 'by the rotatable member and which at their opposite ends areconnected to the base plate 4|. When the angular wall on the under sideof the die member 40 engages the wall 5| of the member 52, the continuedmovement of the die member causes the member 52 to turn in the bearings53, whereby a face 55 on the member 52 engages that portion of the sheet46 which is to form the second side' of the second corrugation and bendsthe said tween, the two positions shownwhile holding it 7 elevated towithdraw the punchassembly I2, and

without disturbingQthe sheet 46 the punch ele ment I3 is lowered to andsecuredin its operative position and the ram of the press againactuated. At this time the punch element |3 moves in front of a guidemember ll and lightly engages the sheet 46 as best shown in Figure 3,while the springs 2| hold the adjacent punch assembly I 4 extended as,this occurs.

'Thereafter as the ram continues its working 'stroke, the plungers 42support the die member v in its elevated position while the springs 2|yield to permit theholder |6to move toward the punch elements 14 and-15.During this relative movement between the holder l5 and'the punchelements I4 and I5, the punch element |3 moves with the holder. As thepunch element I3 is actuated in the manner described, a curved wall ofthe guide acts againstit to cause it to swing inwardly toward andagainst the side wall of the punch element l4 against the action of thespring-loaded pins 31, whereby to form a sidewall and the bottomwall ofa second corcorrugation areformed, the lostmotion between the holder l6and the die elements l4 and I5 istaken up so that thereafter as the ramcontinues its working stroke all of the elements of the punch assemblyl2 and the die member 40 moves as a unit, the pressure'acting againstthe plungers 42 being predetermined to support the said die memberagainst yielding movement until the lost motion between the holder l6and the die elements [4 and |5has been wholly taken up; After the punchassembly and die member side against the cooperating side face of. thepunch element l3. As the die member 40 seats on the bed plate 4|; aradialportion 51 of the rotatable member 52 engages an end wall 58 ofthe die member 40. At this time, therefore, the die member 40 androtatable member 52 form a continuous die cavity in which the punchelement l3 completes its forming operation. Thus, although the punchelement l3, die'member 40 and rotatable member 52 and the sheet mate-.

rial, their final action is that of cooperating male and female dies. ,7

Upon completion of the second corrugation,-the

ram of the press is retracted towithdraw the punch assembly and permitthe elements thereof andthe die members l3 and 52 to be restored totheir original positions. Thepunch element I5 is then lowered to, andsecured in, its operative position and after the sheet 46 has beenadvanced to position the pilot corrugation in the die cavity which thepunch element I5 is to enter and the second corrugation in the cavitywhich the punch element I4 is to enter, the ramis again actuated tocause the punch element l3 to form a third corrugation 59, asillustrated in Figure 4, in the same manner in which the secondcorrugation was formed. Thereafter all of the elements of the punchassembly are employed in each operation of the press. a

It will be noted that in the operation of the forming dies, eachcorrugation, except the pilot corrugation, is initially formed by thepunch element I3 and cooperating die members 40' and 52. Eachcorrugation which is thus formed is thereafter acted upon first by thepunch element l4 and then by the punch element l5. In accordance withthe invention the punch element l3 forms corrugations having side wallswhich are flared less than the final angle of flare pro-' duced-by thepunch elements I 4 'andfl5. This has the advantage that a corrugationwhich has been roughly formed by the punch element l3 will readily enterthe die cavity in which the punch element I4. operates and in which itis sized. The sized corrugations are restruck. by the punchelement I5.Thus after the first two corrugations have been formed each operationofthe dies forms a'new-corrugation, sizes a preformed corrugation andrestrikes a pre-sized corrugation. a

From the-foregoing it will be apparent that in. corrugating thesheet 46in the manner described, no portions thereof are subjected to a drawingaction, hence there is no thinning or stretching of any of the zones ofthe said sheet,

- it being noted in this connection that the punch element l3initiallyiengagesthe sheet"46 (see Figure 3) along a line at which thebend connecting a side wall and the bottom wall of the corrugation willbe formed and that this line of contact is maintained as the said punchelement moves downwardly and at the same time swings inwardly. There isalso very little sliding contact between the sheet 46 and the rotatablemember 52. The dies, therefore, have the further advantage that scoringof the sheet as an incident to the forming operations is minimized.

A further advantage obtained is that at the time a corrugation is beingformed by the punch element l3, the sheet is firmly gripped between thepunch elements l4 and I5 and the die member lil while the punch elementl4 and the said die member provide a straight edge over which the sheetmay be bent. As a result of this and the action of the rotatable member52 in the manner described, the sheet acted upon may be of hardenedstock, it being possible with such stock to form corrugations which maybe held well within the desired tolerances.

We claim as our invention:

1. In a power press having relatively movable opposed working members,the combination of forming dies for corrugating sheet material includinga female die member yieldably carried on one of the working members,companion punch elements carried on the other of said working members,one of which is normally extended and the other of which is normallyretracted, said last mentioned punch element being pivotally mounted onsaid other working member, means for normally holding said lastmentioned punch element in an angular relation with respect to saidfirst mentioned punch element, means for advancing said punch elementswhile holding said die member relatively stationary thereby first tocause said first mentioned punch element to enter a pre-formedcorrugation in said material and said last mentioned punch element thento be advanced with respect to, and to be pivoted toward, said firstmentioned punch element against the action of said first mentioned meansto form part of a second corrugation, said second mentioned means beingthereafter operative to cause yielding movement of said die member andadvance said punch elements and die member as a unit, and means on saidone working member for cooperating with said last mentioned punchelement and said die member and responsive to the movement of the latterfor forming another part of said second corrugation.

2. In a power press having relatively movable opposed working members,the combination of dies for forming straight-sided corrugations in sheetmaterial including a female die member yieldably mounted on one workingmember, companion punch elements mounted on another working member, oneof which is normally extended and the other of which isnormallyretracted, said last mentioned punch element being pivotallymounted on said other working member, means for normally holding saidlast mentioned punch element in an angular relation with respect to saidfirst-mentioned punch element, means for advancing said punch elementswhile holding said die member relatively stationary thereby first tocause said first mentioned punch element to enter a pre-formedcorrugation in said material and said last mentioned punch element thento advance with respect to, and to be pivoted toward, said firstmentioned punch element against the action of said first mentioned meansto form a side and the bottom portions of a second corrugation, saidsecond mentioned means being thereafter operative to cause yieldingmovement of said female die member and advance said punch elements anddie member as a unit, and means on said one working member forcooperating with said last mentioned punch element and said die memberand responsive to the movement of the latter for forming the other sideportion of said second corrugation.

3. In a power press having relatively movable working members, thecombination of forming dies for corrugating sheet material including afemale die member yieldably mounted on one working member, companionpunch elements mounted on the other working member, one of which isnormally extended and the other of which is normally retracted, saidlast mentioned punch element being pivotally mounted on said otherworking member, means for normally holding said last mentioned punchelement man angular relation with respect to said first mentioned punchelement, means for advancing said punch elements while holding said diemember stationary thereby first to cause said first mentioned punchelement to enter a preformed corrugation in said material and said lastmentioned punch element to be advanced with respect to said firstmentioned punch element, a guide on said one working member for causingsaid last mentioned punch element to swing toward said first mentionedpunch element as it is advanced relatively to the latter, whereby toform a part of a second corrugation, said second mentioned means beingthereafter operative to advance said punch elements and die member as aunit, and means on said one working member for cooperating with saidlast mentioned punch element and said die member and responsive to themovement of the latter for forming another part of said secondcorrugation.

4. In a power press having relatively movable Working members, thecombination of dies for forming straight-sided corrugations in sheetmaterial including a female die member yieldably mounted on one of theworking members, companion punch elements movably mounted on the otherWorking member, one of which is normally but yieldably extended and theother of which is normally retracted, means for advancing said punchelements while holding said die member stationary, thereby first tocause said first mentioned punch element to enter a pre-formedcorrugation in said material and thereafter to yield so that said lastmentioned punch element will be in position to form a side wall and thebottom of a second corrugation, said means being thereafter operative toadvance said punch elements and yieldable die member as a unit, andsheet material folding means for cooperating with said last mentionedpunch elementand said die member while they are moving as a unit to folda portion of the sheet material to form the other side of said secondcorrugation, said last mentioned punch element, said die member and saidfolding means cooperating in the forming of the sides of said secondcorrugation so that the angles that they form with respect to the bottomare sharper than the corresponding angles between the sides and bottomof said pre-formed corrugation after being acted upon by said firstmentioned punch element.

JAMES A. WATT. ALFRED J. PERKINS.

